VBT and VBS Treatments for Scoliosis

VBT – Vertebral Body Tethering (tethering), is the newest treatment option available and is challenging the status quo of permanently fusing young spines. Similar to VBS, tethering is a minimally invasive surgical procedure that substantially corrects scoliosis at the time of surgery. Bone screws are anchored to the front of each vertebral bone which makes up the curve and a flexible cord (the tether) is attached to each screw and tensioned to achieve the desired degree of spine straightening. Unlike traditional fusion, VBT allows for continued growth and mobility of the entire spine as well as additional straightening of the spine as the adolescent finishes growing. VBT is best suited for curves 35° to 70°, which are still somewhat flexible. It’s especially good for active preteen and teens, whose continued spine flexibility is desired, but who would otherwise need a traditional spine fusion to keep the curve from getting bigger, stiffer, and more deforming.

Below are some FAQs about VBT.

What is vertebral body tethering?

Vertebral body tethering (VBT), is a “motion sparing”, minimally invasive surgical technique in which pedicle screws are placed into the front of the vertebral bodies and attached to a flexible cable at the bend of the curve. The cable is tightened, which allows some immediate correction of the curve as well as continuing improvement as the spine grows.

Who are candidates for this procedure?

Candidates are patients who are skeletally immature and have a large enough curve that at some point would most likely need spinal fusion whether or not they wear a brace.

Why was VBT developed?

Many patients dislike or cannot tolerate wearing a brace for as often and as long as required in order to keep a curve from getting larger. Vertebral body stapling is another minimally invasive procedure in which staples are placed in the spine to correct the curve. However, VBS has been shown to work well only for thoracic curves less than 35°. A different procedure was needed that worked on larger curves.

What are the specific indications for this procedure?

The primary indication is a thoracic curve between 35° and 70° that has some side-to-side flexibility. The child must still be growing, because part of the correction relies on the cable straightening the spine as the child continues to grow.

Can the procedure be done on people who have stopped growing?

There is a possibility this could be effective for people whose curve has finished growing, but we just don’t know yet.

What happens if VBT does not work?

There have not been any failures yet, but if that were the case, options are still available.The beauty of this procedure is that if tethering does not arrest the curve, the patient can still undergo a spinal fusion. The hope is, at this stage, the spine has grown enough that the patient will not have a short trunk which typically happens when a fusion is done at a younger age.

What does the future hold?

The goal over the next 10 years is to develop improved tethers with more elasticity to accommodate individual patient’s bone growth. We hope to have further insight as to how the spine grows in order to avoid overcorrection of the curve, which can sometimes happen. Improved technology will enable us to apply the procedure to more patients with a wider range of indications.

VBS – Vertebral Body Stapling (stapling) was conceived decades ago as a type of “internal brace” that controls the uneven growth and progressive curvature of the young scoliosis spine. This procedure wasn’t used often, until 2002 when new staples made of a “memory shape alloy” solved the initial concern about a staple becoming dislodged. This began a new paradigm in pediatric scoliosis treatment. It became a movement away from just stabilizing the curve with external bracing, to being able to modulate the growth process of the child’s spine in order to correct the curve. Stapling is a minimally invasive surgical procedure which works best for thoracic curves under 35°, especially for those who, physically or psychologically, are unable to tolerate wearing a brace for as often and as long as necessary to help prevent a curve from progressing.

Below are some FAQs about VBS.

What is vertebral body stapling?

Vertebral body stapling, or VBS or stapling, is a minimally invasive surgical technique in which special malleable metal staples are attached to adjacent vertebral bodies that make up the bend of the curve. These special nickel-titanium alloy staples are cooled and, while in an open position, are placed on the appropriate vertebral segments. As the staples are warmed by the body (which takes less than a minute), they clamp down so they are unable to dislodge. They then keep the curve from progressing by slowing the growth on the convex (protruding) side of the curve while allowing the spine’s own natural growth on the concave (recessed) side.

Who are candidates for this procedure?

Candidates are patients who are still growing, are older than seven years of age and have a large curve that continues to get worse. Young patients who have not yet started puberty and have been recommended many years of brace wear are most likely to benefit from this procedure.

Why was VBS developed?

Many young patients dislike or cannot tolerate wearing a brace for as often and as long as required in order to keep a curve from getting larger. The idea of an “internal brace” that would work 24/7 to keep a curve from getting larger may be particularly attractive. In some cases, stapling would not just hold the curve but also correct the curve as well.

What are the specific indications for this procedure?

The primary indication is a thoracic curve of 25 to 35 degrees or a lumbar curve less than 45 degrees in a still growing patient. The curve’s flexibility has to be less than 20 degrees.

Can the procedure be done on people who have stopped growing?

No since the benefits of the procedure would be minimal.

What happens if VBS does not work?

Should the curve continue to progress all the same treatment options remain available. For example, Vertebral Body Tethering (VBT) is still a possible option, as is a traditional spinal fusion. Although the patient may still need a spinal fusion they would have benefited from additional growth as well as time without having to wear a brace.

Need more in depth information about VBT and VBS? Here are two links that may help…

Pediatric Spine Foundation

Let’s Get Ahead of the Curve!

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